JPH05315728A - Transfer sheet and manufacture of circuit element using it - Google Patents

Abstract

PURPOSE:To provide a transfer sheet having strong adhesive force between the circuit part of a transfer sheet and an insulated substrate of a circuit element at the time of manufacturaing the circuit element while having little variation in the size of the circuit part at the time of manufacturing the circuit element. CONSTITUTION:An electrode pattern 2 is provided on a base material part 1 consisting of a flexible film and an insulator layer 3 is provided on the electrode pattern 2 while providing adhesive layer 6 on the upper end part of the insulator layer 3 in order to increase adhesive force at the time of lamination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer sheet for realizing a high-density mounting circuit and a method for manufacturing a circuit element using the transfer sheet.

[0002]

2. Description of the Related Art There is a technique of using a multi-layer substrate as an electronic circuit forming technique corresponding to the recent high function and high density mounting of electronic equipment. Although this technology has been introduced in the field of large-sized computers, it has recently been actively used in the field of portable electronic devices that require miniaturization, such as video movies, mobile phones, and personal computers.

A conventional transfer sheet for realizing a circuit element using a multi-layer substrate is shown in the top view of FIG.
As shown in the sectional view of (b), an electrode pattern 2 is provided on a base material portion 1 made of a flexible film, and an insulating layer 3 is provided on the electrode pattern 2, 2 and the insulator layer 3 constitute the circuit portion 4. Then, as shown in FIG. 4, the method of manufacturing a circuit element using the transfer sheet described above uses the transfer sheet of FIG. 3 on the insulating substrate 5 to form the circuit portion 4 including the electrode pattern 2 and the insulating layer 3. One or more layers were transferred onto the insulating substrate 5 to form a laminate, and the laminate was subjected to thermocompression bonding, binder removal, and main firing in this order.

[0004]

However, when the conventional transfer sheet is used, there is a problem that the transfer sheet is easily peeled off at the interface between the circuit portion 4 and the insulating substrate 5. The reason is that the insulating layer 3 is a mixture of resin and inorganic powder and has a weak adhesive force with the insulating substrate. If the content of the resin is increased in order to increase the adhesive strength, the adhesive strength is increased, but there is a problem that the shrinkage becomes large at the time of manufacturing the circuit element.

The present invention solves the above-mentioned problems of the prior art. The circuit sheet of the transfer sheet and the insulating substrate of the circuit element have a strong adhesive force at the time of manufacturing the circuit element, and the dimension of the circuit section changes at the time of manufacturing the circuit element. An object of the present invention is to provide a transfer sheet having a small amount and a method for manufacturing a circuit element using the transfer sheet.

[0006]

In order to achieve the above-mentioned object, a transfer sheet of the present invention is provided with an electrode pattern on a base material part made of a flexible film, and an insulating layer on the electrode pattern. Is provided, and an adhesive layer is provided at the upper end of the insulating layer.

[0007]

According to the above construction, the adhesive force with the insulating substrate can be increased without increasing the dimensional change of the circuit portion during the production of the circuit element.

[0008]

(Embodiment 1) A first embodiment of the present invention will be described below with reference to FIG.

FIG. 1A is a top view of the transfer sheet of this embodiment, and FIG. 1B is a sectional view taken along the line AB. In these figures, reference numeral 1 is a base material portion made of a flexible film such as polyester subjected to a mold release treatment. Reference numeral 2 is an electrode pattern formed by a printing method using a copper electrode paste. 3 is an insulator layer provided on the electrode pattern 2 by a printing method,
The thickness after drying was set to 100 μm. The insulator layer 3 is composed of 12% by weight of resin and plasticizer, and 88% by weight of inorganic powder of glass and alumina. Reference numeral 6 is an adhesive layer provided on the upper end of the insulating layer 3 by a printing method. The adhesive layer 6 is made of the same resin and plasticizer as the insulator layer 3 and contains no inorganic powder.
The resin used in this example was composed of two components of polyvinyl butyral and alkylphenol, the plasticizer was composed of three components of dioctyl phthalate, dibutyl phthalate and butylbenzyl phthalate, and α-terepinol was used as the organic solvent.

Even if the polyester film 1 is peeled by heat-pressing the transfer sheet of this embodiment to the insulating substrate 5 made of forsterite via the adhesive layer 6, peeling is recognized between the circuit portion 4 and the insulating substrate 5. I couldn't do it.

Example 2 Next, a method of manufacturing a circuit element using the transfer sheet of Example 1 will be described with reference to FIG.

In the figure, a cross section is formed by performing transfer three times using the transfer sheet of Example 1 on an insulating substrate 5 made of forsterite to form a laminate, and subjecting the laminate to thermocompression bonding. It is a figure. This cross section is different from the conventional example in that the adhesive layer 6 is embedded in the end portion of the circuit portion 4. Since the electrode pattern 2 of this embodiment uses a copper electrode paste, the binder is removed with an oxygen concentration of 50.
24 at a maximum temperature of 500 ° C in an atmosphere of ppm or less
It was heated for a period of time to remove the solvent, the resin, and the organic material of the plasticizer. Then 900 in a nitrogen atmosphere
Main firing was performed by heating at 0 ° C. for 10 minutes. No defect such as peeling occurred between the circuit portion 4 and the insulating substrate 5 in the circuit element manufactured in this manner.

(Embodiment 3) The transfer sheet of this embodiment is different from the transfer sheet of Embodiment 1 in that the electrode pattern is Ag /
Using Pd electrode paste as an inorganic powder for the insulator layer
The point is that glass that is sintered at 00 ° C. and alumina are used, butyral is used as the resin, butylbenzyl phthalate is used as the plasticizer, and butyl carbitol is used as the organic solvent. The adhesive layer was made of the same resin and plasticizer as those of the above-mentioned insulator layer and contained no inorganic powder.

No peeling was observed between the circuit section 4 and the insulating substrate 5 even if the polyester film was peeled off by thermocompression bonding the transfer sheet of this Example to an insulating substrate made of alumina via an adhesive layer.

Example 4 Next, a method of manufacturing a circuit element using the transfer sheet of Example 3 will be described.

The transfer sheet of Example 3 was used to transfer onto the alumina substrate three times to form a laminate, which was subjected to thermocompression bonding. Since the electrode pattern of this example uses Ag / Pd electrode paste, the binder was heated in air at a maximum temperature of 500 ° C. for 24 hours to remove the solvent, the resin, and the organic material of the plasticizer. Then, it was heated in air at 900 ° C. for 10 minutes to be subjected to main firing. No defect such as peeling occurred between the circuit portion 4 and the insulating substrate 5 in the circuit element manufactured in this manner.

(Example 5) A transfer sheet of this example is different from the transfer sheet of Example 1 in that a copper oxide electrode paste is used for an electrode pattern and a crystallization temperature of 850 ° C. is used as an inorganic powder for an insulating layer. The glass powder in which the average particle size of calcium borosilicate was adjusted to 1.5 μm was used, the solvent was a mixed solvent of butyl cellosolve and butyl carbitol acetate, and the same resin and plasticizer were used.

No peeling was observed between the circuit portion 4 and the insulating substrate 5 even if the polyester film was peeled off by thermocompression bonding the transfer sheet of this example to the insulating substrate made of steatite via the adhesive layer. ..

(Sixth Embodiment) Next, a method of manufacturing a circuit element using the transfer sheet of the fifth embodiment will be described.

The transfer sheet of Example 5 was used to transfer onto the steatite substrate three times to form a laminate, which was subjected to thermocompression bonding. Next, the binder was removed by heating in air at a maximum temperature of 500 ° C. for 24 hours. Since the electrode pattern of this example uses a copper oxide electrode paste, it was heated in a hydrogen atmosphere at 250 ° C. for 1 hour to reduce the copper oxide to copper. Then 900 ° C in a nitrogen atmosphere
The main firing was performed for 10 minutes. No defect such as peeling occurred between the circuit portion 4 and the insulating substrate 5 in the circuit element manufactured in this manner.

In the examples, the printing method was used to form the electrode pattern, the insulating layer and the adhesive layer of the transfer sheet, but instead of this, a doctor blade method, a casting method, a concave plate printing method, a flat plate printing method. May be used.

[0022]

As is apparent from the above description, according to the present invention, the following effects can be obtained.

(1) A transfer sheet having a strong adhesive force between the circuit portion and the insulating substrate and having little dimensional change before and after thermocompression bonding can be obtained.

(2) It is possible to manufacture a high-density circuit element having no defects such as peeling between the circuit portion and the insulating substrate.

[Brief description of drawings]

1A is a top view of a transfer sheet according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line AB of FIG. 1A.

FIG. 2 is a cross-sectional view of a laminate in the method for manufacturing a circuit element of the present invention.

3A is a top view of a conventional transfer sheet, and FIG. 3B is a cross-sectional view taken along the line C-D of FIG. 3A.

FIG. 4 is a cross-sectional view of a laminated body in a conventional circuit element manufacturing method.

[Explanation of symbols]

 1 Base Material Section 2 Electrode Pattern 3 Insulator Layer 4 Circuit Section 5 Insulating Substrate 6 Adhesive Layer

Claims (2)

[Claims] 1. A transfer in which an electrode pattern is provided on a base material portion made of a flexible film, an insulating layer is provided on the electrode pattern, and an adhesive layer is provided at an end portion on the insulating layer. Sheet. 2. A laminated body is formed by transferring one or more layers of a circuit portion consisting of an electrode pattern, an insulating layer and an adhesive layer in the transfer sheet according to claim 1 onto an insulating substrate to form a laminated body, and thermocompression bonding is applied to the laminated body. , A method for manufacturing a circuit element in which binder removal and main firing are sequentially performed.